upgrade pip

.travis.yml

@@ -9,14 +9,13 @@ python:
 
 before_install:
   - sudo apt-get install -y pandoc pandoc-citeproc texlive
-  - python3 -m pip install --upgrade pip
 
 addons:
   apt:
     update: true
 
 # Command to install dependencies, e.g. pip install -r requirements.txt --use-mirrors
-install: pip install tox-travis
+install: pip install --upgrade pip && pip install tox-travis
 
 # Command to run tests, e.g. python setup.py test
 script: tox